The present invention relates to an axial piston pump apparatus, and particularly relates to an improvement in a drive mechanism for driving a cylinder barrel or a swash plate of the same apparatus.
An axial piston pump has a structure wherein plural pistons are arranged in parallel with an axis of a rotary cylinder barrel, and one end of each piston is pivotally supported on a drive shaft or a swash plate which is inclined to the cylinder barrel. The pistons are reciprocally moved in respective cylinder bores provided in the cylinder barrel as the cylinder barrel is rotated, and thereby perform suction and discharge.
The axial piston pump with such a structure is disclosed in Japanese Patent Examined Publication No. 59-5794, for example. In the axial piston pump taught in this publication, all the pistons serve as drive pins to transmit torque to the cylinder barrel as well as carry out suction and discharge.
In contrast to the axial piston pump of this publication, the inventors have proposed an axial piston pump structure in which drive pins are provided to transmit turning force or torque separately from the pistons. This axial piston pump is disclosed in Japanese Patent Unexamined Publications Nos. 63-309785, 64-12079 and 1-77771, the last publication of which corresponds to U.S. Pat. No. 4,884,952 issued on Dec. 5, 1990.
As described in detail later, it is however necessary to improve further the drive mechanism of the axial piston pump in view of reduction in noise, vibration and size.